In operating recent computer applications, electrical appliances, or the like, which have a great variety of functions, an enormous number of functions can be performed. As interfaces for allowing the enormous number of functions to be performed more easily, selecting-type interfaces having a hierarchical structure are adopted in many applications or pieces of equipment.
In these selecting-type interfaces, the user sequentially selects, from among a plurality of selectable options as designed by a system designer, options which the user considers to be closest to his or her aim, thereby finally accomplishing a desired function. Thus, even a beginner who does not know an exact procedure to be followed in order to perform the desired function can cause the device to perform that function easily.
However, in the case where a system developer's design concept does not agree with aims which the user conceives from the selectable options, the desired function might not be reached, even if the user sequentially selects options that are close to his or her aim. Thus, an assistance is needed that, when the user cannot reach the aim, properly grasps the function demanded by the user based on user input information (the options that have actually been selected so far) and informs the user of an operational procedure to cause the device to perform the corresponding function and a description of that function.
In order to overcome such a problem, a help display device (see Patent Reference 1) has been disclosed that, with each key and each function that can be performed in a system being defined by a system developer beforehand using feature vectors, searches for a function desired by a user by calculating a distance between a feature vector calculated based on a collection of key inputs selected by the user and a feature vector of each function, and presents a result of the search. More specifically, vectors that characterize descriptions of the functions and the keys, such as a “cursor key”, “Space”, and “Delete”, are generated based on characteristic words (e.g., move, up, down, right, delete, insert, etc.) previously defined by a system designer. If the user presses a Help button while editing text, for example, the vectors generated in such a manner are used to generate, based on a history of a key input operation performed before the pressing of the Help button, a key input operation vector representing a characteristic of the key input operation, and calculate a distance between that vector and a vector representing a characteristic of each function, whereby an editing operation desired by the user is estimated.    Patent Reference 1: Japanese Unexamined Patent Application Publication No. 11-231998